This invention relates to a integrated mechanical and electronic system to give length measurements of electrical conduit above and below ground.
Over the years electricians have measured electrical conduits with a True Tape. True Tape is constructed of flat fiber string imprinted with foot increments. It has always been the procedure to vacuum in a seperate string in order to pull the True Tape through the conduit. Once the string is through the entire run of conduit the True Tape is then attached to the string. The True Tape must then be physically pulled through the conduit to the other end in order to get the readings on each end in feet. Subtracting the foot measurement at one end from the measurement at the opposite end has always been the only means to calculate the total number of feet of cable or conductor necessary.
One of the most formidable problems in using True Tape is brought on by the water that settles in underground conduits. This causes difficulty to pull the True Tape in because it sticks to the inner walls of the conduit, breaks easily and cannot be vacuumed in. These factors force the workers to manually pull the True Tape through. There is always that high risk of the True Tape breaking and they need to start at square one again.
Another drawback is that the synthetic fiber True Tape is composed of gets weighted down by the mud and water in the pipe and it causes drag and friction. Resulting in cutting and scoring along the pvc walls of extended lengths of conduit. There are many types of True Tape, yet even the larger sizes, that don't do such damage, still are required to be pulled in by hand.
This method of measuring has always been a slow process and uses vast amounts of man hours. Hence we need an accurate and reliable way of measuring the length of electrical conduit in the field. My invention is to provide a new way, that will avoid these problems.